A Reddit thread asks if Google engages in link-buying sting operations where they will pretend to want to buy a link and then use that to penalize the network. John Mueller of Google responded by saying, "I get sent offers all the time to an official Google email address." That means, Google does not need to do that proactively; they come to Google without any official or necessary operation.
This question came up on Reddit, "That is, do they send out spam, disguised as marketers, to bloggers and publishers, asking to buy links on their websites, and then after completing the transaction, delisting them from Google for violating the paid links rule?"
I don't think Google does this, but I know Googlers have received such communication via email over the years, unsolicited. And as John said, they even send them to official Google email addresses.
It seems like Google may use these emails against the network. This is not the first time Google has said this. Gary Illyes from Google in 2017 where someone emailed him about link buying based on DA. Heck, even in 2016, someone emailed Matt Cutts with paid link requests and in 2012 they sent it to a different Googler. In 2019, Gary Illyes from Google said they even talked to these folks. It is not smart to ask Googlers who work on Google Search to break their webmaster guidelines.
I know you all get these emails, not once or twice a month, but more like several times a day. So I am not surprised these go to Googlers without any need for Google to try to do some special operation to get them.
Forum discussion at Reddit.